emily56 on "[Theme: WP Simple] Menu disappears on header bar when scrolling through banner row"

Hello! I'm trying to make a fixed, white, non-transparent menu bar on the top. When I start scrolling down, the menu bar changes color to white and the menu items are getting disappear(eiter transparent or white) - this lasts until the end of banner row. After the banner row, it appears again - but changes color to black(to default color).
I guess this can be adjustable in the public.js file. When I delete the lines 15-22, it works fine(just the banner crashes). Since I'm not familiar with js at all, I ask you about the changes I should made in that file. Or any other files.
Thank you very much!

Well, I forgot to say: I don't want any js effect on the header menu at all.